The invention concerns a fastener for construction systems, especially for exhibition booths, comprising tubes and nodes, with one screw attaching to a tube and another attaching to a node, whereby the screws are accommodated axially aligned in a sleeve that surrounds at least their heads, leaving their threaded shafts extending out and whereby the node-attached screw slides back and forth but cannot rotate in the sleeve and is secured to the tube-attached screw by a threaded bolt that extends through a bore in the latter.
Systems for constructing exhibition booths for trade shows, etc. are available in the form of kits comprising tubes and nodes. The nodes can be essentially spherical for example and have inside-threaded bores oriented in different directions. Strut in the for of tubes can be secured to the nodes by fasteners to produce a coherent structure.
One known fastener features a node-attached screw that move axially in relation to a hexagonal sleeve but cannot be countersunk. The fastener is attached to the tube and the hexagonal sleeve is manipulated with a wrench. The outside diameter of the fastener is identical for every pipe diameter encountered in booth construction.
Another known fastener has an axially movable node-attached screw that, although it can be countersunk, cannot be locked into that position. The screw moves freely and is secured in its hexagonal sleeve by a spring. The fastener has a threaded section that screws into the tube and can accordingly be replaced. Once the structure has been erected, this known fastener can definitely be distinguished from the tube. There is only one format that is employed with every diameter of tube.
A third fastener consists of two jaws or flaps that are secured together by a cylindrical countersinking-head screw. The two flaps connect the tube to the node, specifically by way of locking screws that screw onto the tube and node separately. The two flaps have the same outer cross-section as their associated tubes and look like extensions of the tube. Still they are obviously due to their two-part structure, fasteners.
The known fasteners have many drawbacks.
The construction of exhibition booths presupposes a flexible approach to ensure effective results. It must be possible to assemble and disassemble the booth rapidly and easily and to replace defective components, separate the fasteners from the tubes, and interchange the tubes without any problems. The appearance of the booth must also not suffer from unattractive fasteners. Constantly erecting and dismantling the booths is hard on the system's components, and they are often exposed to awkward handling. The threaded components that secure the fastener to the nodes are particularly sensitive to damage. It is accordingly desirable to protect the threads, at least until they are used. None of these requisites are satisfactorily fulfilled, if at all, by the fasteners known up to now.